Secretary of State John Kerry said Wednesday it will take time for airstrikes to degrade the terror group ISIS, echoing previous comments by President Barack Obama.

In an exclusive interview with CNN's Christiane Amanpour, Kerry said, "There's a definitely a second day and there will be a third and more. This is going to go on."

The United States and coalition members conducted a second day of airstrikes Tuesday night in Syria and Iraq since the expanded military campaign against the extreme terror group began.

The campaign will be lengthy, Kerry said, partly because the Iraqi military needs to be reconstituted, and because it will take time to arrange the kind of local support similar to the Sunni Awakening years ago.

Kerry insisted, however, that airstrikes aren't designed to defeat ISIS by themselves. "You and others should not be looking for some massive retreat in the next week or two," he told Amanpour.

While Kerry said airstrikes haven't flushed out ISIS in Iraq, they have "stopped the onslaught," and have been effective in halting ISIS' march toward Irbil and Baghdad and prevented them from taking other important territory.

The secretary of state said the battle to stop ISIS is a multifaceted effort that includes foreign fighters, cutting off financing, and a major effort to "reclaim Islam by Muslims."

ISIS is a threat to the people in the region, he said, but also to national sovereignty.